The present invention is directed to integrated circuits. More particularly, the invention provides systems and methods for source switching and/or internal voltage generation. Merely by way of example, the invention has been applied to a power conversion system. But it would be recognized that the invention has a much broader range of applicability.
Conventional switch-mode power supplies often implement gate controlled switching using high voltage power MOSFETs. But high voltage start-up circuits for such switch-mode power supplies are usually manufactured using an expensive high voltage semiconductor process. In addition, the conventional switch-mode power supplies often suffer from slow start-up and high standby power consumption.
Hence, it is highly desirable to improve switching schemes of a power conversion system.